Communication system, communication apparatus, communication method, and non-transitory medium

ABSTRACT

A first data center includes a first virtual network that provides a communication service in cooperation with at least a part of a communication facility of a first communication operator and a first communication unit that is operable to communicate with a second data center. The second data center includes a second virtual network that provides a communication service in cooperation with at least a part of a communication facility of a second communication operator and a second communication unit that is operable to communicate with the first data center. The first communication unit is operable to transmit to the second communication unit, communication data to be transmitted from a first terminal connecting to the first virtual network via a communication facility of the first communication operator to a second terminal connecting via a communication facility of the second communication operator to the second virtual network.

DESCRIPTION OF RELATED APPLICATION

This application is a National Stage of International Application No.PCT/JP2016/058426, filed on Mar. 17, 2016, which claims the benefit ofJapanese Patent Application No. 2015-054721, filed Mar. 18, 2015, whichis hereby incorporated by reference herein in its entirety.

TECHNICAL FIELD

The present invention relates to a communication system, a communicationapparatus, a communication method, and a non-transitory medium.

BACKGROUND

Roaming is a service whereby a service of a communication operator withwhich a user contracts can be received, even outside a service range ofthe communication operator, by using a communication facility of anothercommunication operator with which the one communication operatorcooperates. By using an international roaming service, a service can bereceived in overseas by using a facility of an overseas local operator.

It is to be noted that, among communication operators, a communicationoperator borrowing a necessary infrastructure(s) from a communicationoperator (Mobile Network Operator: MNO) (also referred to as a “carrier”or “MNO carrier”) having a wireless infrastructure such as a basestation or a communication facility such as a core network and the like,and providing a mobile communication service under its own brand, iscalled a virtual communication operator (Mobile Virtual NetworkOperator: MVNO). A virtual communication operator is also called “MVNOcarrier”.

In connection with roaming, for example, Patent Literature 1 discloses atechnique which makes it possible for a remote communication terminal(User Equipment: UE) to perform a local IP (Internet Protocol) access toa locally accessible network with a simpler procedure, while realizingefficiency of cost and equipment. When establishing a PDN connectionbetween LIA (Local IP Access)-PDN (Packet Data Network), UE alsotransmits information on the LIA domain network that desires local IPaccess. Based on this information, the LIA-PDN establishes a PDNconnection with the LIA domain network, and the LIA-PDN performs packettransfer so that the UE accesses the LIA domain network through thesePDN connections.

Patent Literature 2 discloses a method wherein an option related to acommunication session on a network related to MVNO receiving an accessrequest from a client, at least one MNO out of a plurality of MNO sets,and a selected communication session is established.

Patent Literature 3 discloses a common-base communication apparatus,wherein when a user who has made a contract with a first licensedcommunication operator permitted to provide a wireless communicationservice to a wireless communication terminal issues a connection requestfrom an area where a second licensed communication operator provides awireless communication service, even if the first licensed communicationoperator and the second licensed communication operator do not have aroaming service contract, the second licensed communication operatorperforms control to connect a wireless communication terminal located inan area in which the second licensed communication operator provides thewireless communication service, to a requested communicationdestination.

Patent Literature 1: WO2011/048768A

Patent Literature 2: JP Patent Kohyo Publication No. 2011-538532A

Patent Literature 3: JP Patent Kokai Publication No. 2012-219799A

NON-PATENT LITERATURE

Non-patent Literature 1:

Yuichi Suwa et al., “Realization of Packet International RoamingCommunication with xGSN”, NTT Docomo Technical Journal, Vol. 12, No. 4,Feb. 6, 2015 Search, Internet URL:https://www.nttdocomo.co.jp/binary/pdf/corporate/technology/rd/technical_journal/bn/vol12_4/vol12_4_039jp.pdf

SUMMARY

The analysis of the related art is given below.

The inventors of the present invention have newly found an issue to makeit possible to eliminate roaming between carriers at the time of roamingof a terminal of a user contracting with a MVNO carrier, and invented ameans to solve the issue. It is noted that none of the PatentLiteratures 1 to 3 discloses any recognition of the issue.

An object of the present invention is to provide a system, an apparatus,a method, and a non-transitory medium storing a program for solving theabove issue.

According to one aspect of the present invention, there is provided acommunication system comprising:

at least a first data center providing a cloud service to a user,wherein the first data center comprises:

a first virtual network that provides a communication service incooperation with at least a part of a communication facility of at leasta first communication operator; and

-   -   a first communication unit that is operable to communicate with        a second communication unit in a second data center, wherein        first communication unit is operable to transmit to the second        communication unit, communication data to be transmitted from a        first terminal connecting to the first virtual network via the        communication facility of the first communication operator to a        second terminal connecting via a communication facility of a        second communication operator to a second virtual network in the        second data center, the second virtual network providing a        communication service in cooperation with at least a part of the        communication facility of the second communication operator.

According to another aspect of the present invention, there is provideda communication apparatus constituting a network of a first data centerthat provides a cloud service to a user, the apparatus comprising

-   -   a first unit configured to connect to a first virtual network        that is included in the first data center and provides a        communication service in cooperation with at least a part of a        communication facility of a first communication operator, the        first unit being operable to communicate with a second data        center including a second virtual network providing a        communication service in cooperation with at least a part of the        communication facility of a second communication operator; and    -   a second unit configured to control a transmission destination        of communication data transmitted by the first unit, the second        unit controlling the first unit to transmit to the second data        center, communication data that is to be transmitted from a        first terminal connecting via a communication facility of the        first communication operator to the first virtual network to a        second terminal connecting via a communication facility of a        second communication operator to the second virtual network.

According to another aspect of the present invention, there is provideda non-transitory computer-readable recording medium storing therein aprogram causing a computer of a communication apparatus constituting anetwork in a first data center providing a cloud service to a user, toexecute:

-   -   a first processing to connect to a first virtual network that is        included in the first data center and provides a communication        service in cooperation with at least a part of a communication        facility of a first communication operator, the first processing        operable to communicate with a second data center including a        second virtual network providing a communication service in        cooperation with at least a part of the communication facility        of the second communication operator; and    -   a second processing to control a transmission destination of        communication data transmitted by the first processing,    -   the second processing controlling the first processing to        transmit to the second data center, communication data that is        to be transmitted from a first terminal connecting to the first        virtual network via a communication facility of the first        communication operator to a second terminal connecting via a        communication facility of a second communication operator to the        second virtual network.

According to another aspect of the present invention, there is provideda communication method comprising:

-   -   a first data center that provides a cloud service, by using a        first virtual network that provides a communication service in        cooperation with at least a part of a communication facility of        a first communication operator, and a first communication unit,        being operable to communicate with a second communication unit        in a second data center that provides a cloud service and a        second virtual network that provides a communication service in        cooperation with at least a part of communication facility of a        second communication operator; and    -   communication data from a first terminal connecting via the        communication facility of the first communication operator to        the first virtual network in the first data center, being        capable to be transmitted via the first communication unit of        the first data center and via the second communication unit of        the second data center, to a second terminal connecting via the        communication facility of the second communication operator to        the second virtual network in the second data center.

According to the present invention, a terminal of a user contracted toan MVNO carrier can eliminate roaming between carriers when roaming.Still other features and advantages of the present invention will becomereadily apparent to those skilled in this art from the followingdetailed description in conjunction with the accompanying drawingswherein only exemplary embodiments of the invention are shown anddescribed, simply by way of illustration of the best mode contemplatedof carrying out this invention. As will be realized, the invention iscapable of other and different embodiments, and its several details arecapable of modifications in various obvious respects, all withoutdeparting from the invention. Accordingly, the drawing and descriptionare to be regarded as illustrative in nature, and not as restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating Related Invention 1.

FIG. 2 is a diagram illustrating Related Invention 2.

FIG. 3 is a diagram illustrating Related Invention 3.

FIG. 4 is a diagram illustrating Related Invention 4.

FIG. 5 is a diagram illustrating Related Invention 4.

FIG. 6 is a diagram illustrating a basic configuration of exampleembodiment 1.

FIG. 7 is a diagram illustrating Example Embodiment 1;

FIG. 8 is a diagram illustrating Example Embodiment 1;

FIG. 9 is a diagram illustrating a basic configuration of ExampleEmbodiment 2.

FIG. 10 is a diagram illustrating a basic configuration of ExampleEmbodiment 3.

FIG. 11 is a diagram illustrating a modification of Example Embodiment4.

FIG. 12 is a diagram illustrating a modification of Example Embodiment5.

FIG. 13 is a diagram illustrating a configuration example of acommunication apparatus (gateway) according to Example Embodiment 1 andthe other Example Embodiments.

DETAILED DESCRIPTION

In the following, related inventions, as premises of the presentinvention will be described, and then several Example Embodiments of thepresent invention will be described.

In SDN (Software Defined Network)/NFV (Network Function Virtualization),a plurality of network appliances, each of which individually requires acasing, are integrated on a server using virtualization technology. Forexample, virtualization such as an Evolved Packet Core (EPC) which is acore network of a communication operator (carrier) is in progress. In avirtualized EPC (Virtualized EPC: vEPC), at least one or all of nodes,such as SGW (Serving Gateway), PGW (PDN (Packet Data Network) Gateway),MME (Mobility Management Entity), HSS (Home Subscriber Server), PCRF(Policy and Charging Rules Function), is(are) implemented in asoftware-based manner by an application(s) operating on the virtualmachine(s).

For example, a virtual EPC network (vEPC) that virtualizes EPC can beimplemented on a general-purpose server or the like disposed in a datacenter (DC) that provides a cloud service (or data center service) to aclient can do.

Each element (function) of an EPC network will be briefly described here(for details, reference may made to 3GPP TS 23.401 V 9.5.0 (2010 June)etc)). MME performs various type of processing, such as mobilitymanagement and authentication of a terminal (mobile terminal) 1 (UE),setting of a user data transfer path, and so forth. In addition, MMEcooperates with HSS to authenticate a user. HSS holds user profileinformation (including contract information, authentication information,etc.). SGW performs transmission and reception of user data to and froma base station, and performs setting and release of a communication pathbetween SGW itself and PGW. PGW connects to a packet data network (PDN)such as IMS (IP Multimedia Subsystem) or the Internet and allocates anIP (Internet Protocol) address (private IP address) to a terminal. PCRFis a policy control apparatus that determines policy control such as QoS(Quality of Service) and an accounting control rule. Based onnotification information (policy) from PCRF, PGW and SGW perform policycontrol on a per packet basis, for example.

FIG. 1 is a diagram for explaining Related Invention 1. In thefollowing, it is assumed that a data center operator having a datacenter (DC) within a business establishment is a cloud operator thatprovides various data center services as cloud services (for example,file storage, data sharing, electronic-mail, use of a server, etc.) toclients. A virtual EPC network (vEPC) 32 is constructed on a server (notillustrated) in the data center (DC) 30, whereby, as an MVNO carrier(MVNO carrier C), a communication service is provided to a client.

A cloud operator (in this example, a cloud operator is MVNO carrier C)provides a communication service using a virtual network (VirtualNetwork) constructed by borrowing a communication facility 10 such as abase station 11 lent from the MNO carrier. A terminal 1 is connected,via the base station 11 of an MNO carrier A, a gateway (GW), and theInternet 20, to a virtual EPC network 32 on a server (not illustrated)installed in the data center 30 of the cloud operator. The terminal 1receives, via the virtual EPC network 32, Internet connection service,cloud type content cache service and so forth that are provided by thecloud operator. In the example of FIG. 1, an enterprise network 33 isalso made cloud-based by using a server virtualization technology, and anetwork virtualization technology such as VLAN (Virtual Local AreaNetwork), or the like. In FIG. 1, in place of the virtual EPC network(vEPC) 32, an EPC network based on an actual machine without usingvirtualization (MVNO carrier C's own EPC) may, as a matter of course, beprovided in the data center 30. In FIG. 1, a VPN (Virtual PrivateNetwork) may be provided for connection between the terminal 1 and thegateway 31, or between the terminal 1 and the enterprise network 33.

FIG. 2 is a diagram illustrating Related Invention 2. Only the virtualEPC network 32 is operated in the data center (DC) 30 of the cloudoperator, while facilities (base stations) owned by a plurality ofcarriers are used. When a facility with a small investment amount like afemtocell is used, the cloud operator itself may install the basestation. In the example of FIG. 2, a base station 11C is a base stationof a femtocell, a facility 10 C including the base station 11 C and agateway (GW) 12C is a communication facility owned by a cloud operatorthat owns the data center (DC) 30. Therefore, regarding the facility 10Csuch as the base station 11C and the gateway 12C, the cloud operator isalso an MNO carrier.

On the other hand, in the case wherein a cloud operator that owns thedata center (DC) 30 borrows an owned facility 10 A of the carrier A anda owned facility 10 B of the carrier B, and, by using the ownedfacilities 10 A and 10 B, provides a communication service to a terminalof a user contracting with the cloud operator, the cloud operator willconduct a business as MVNO carrier C. It is a matter of course thatinstead of the virtual EPC network 32 in FIG. 2, an EPC network based onan actual machine without virtualization may be provided.

FIG. 3 is a diagram for explaining Related Invention 3. In RelatedInvention 3, terminals 1A and 1B of users contracting respectively withthe carrier A and carrier B which are MNO carriers connect to an EPCnetwork 13A owned by the carrier A and an EPC network 13B owned by thecarrier B, respectively.

In FIG. 3, a terminal (not illustrated) contracting with an MVNO carrierC (cloud operator) that borrows communication facility such as the basestation 11A or 11B from the carrier A or B is connected to a virtual EPCnetwork 32 in the data center 30 of the cloud operator.

FIG. 4 is a diagram illustrating Related Invention 4. In FIG. 4 as well,as in FIG. 3, a cloud operator, which is a data center operator thatowns a data center (DC), becomes an MVNO carrier C. As a facility suchas a base station, etc, an existing facility of an MNO carrier or an ownfacility of the carrier C may be used.

In FIG. 4, an international roaming (international roaming acrossdifferent carriers) is schematically illustrated in which a service ofthe carrier A with which the terminal has contracted in Japan (Japan:JP) is received in US (United States of America) by using communicationfacility of another carrier B that the carrier A cooperates. When theroaming is performed, a technique for establishing a tunnel between aroaming source carrier and a roaming destination carrier, orcommunication using NAT (Network Address Translation) is used (forexample, reference may be made to Non-Patent Literature 1). There is amode in which direct connection is implemented by a GTP (GPRS (GeneralPacket Radio Service) Tunneling Protocol) tunnel between a packet relayapparatus of a core network of a carrier of a roaming source and apacket relay apparatus of a core network of a roaming destinationcarrier. In a packet relay apparatus that allocates a private IP addressto a terminal, when sending a packet from the terminal to an overseasnode subscribing to an overseas communication carrier, the packet relayapparatus converts the private IP address of the packet to a global IPaddress using a NAT function and sends the packet to a roaming relayoperator, which converts the global IP address of the packet from a nodeof an overseas communication carrier to a private IP address to transferthe packet.

FIG. 5 schematically illustrates a situation in which a user moves fromJapan to US in the system of FIG. 4 and a base station 11 B and so forthof the US carrier B are used.

In Japan, a terminal 1 connects to an EPC network 13A of the carrier Avia a base station 11A (Step 1). The user moves to the US (Step 2). Theuser's terminal 1 connects to an EPC network 13B of the carrier B of theUS via a base station 11B and starts communication by roaming (Step 3).

It is noted that in FIG. 4, there is included an arrangement wherein theterminal 1 communicating with the facility owned by the carrier Acommunicates with a terminal of the connection destination in the Unitedstates (a terminal communicating with facility owned by the carrier B inthe United states) by using the international roaming function.

Example Embodiment 1

FIG. 6 is a diagram illustrating a basic configuration of ExampleEmbodiment 1. In the example of FIG. 5, carrier roaming (JP carrier A toUS carrier B) is performed across countries between Japan and the UnitedStates. Contrary to this, referring to FIG. 6, in Example Embodiment 1,inter-carrier roaming across countries is not performed. That is, aterminal 1 of a user contracting with a MVNO carrier C connects to abase station 11A of the facility 10A of a Japanese carrier A (MNO) inJapan, and communicatively connects from the gateway 12 A via theInternet 20 to a virtual EPC network 32C-1 via a gateway (GW) 31C-1 ofthe data center (DC-1) 30-1 owned by a MVNO carrier that provides acloud service. The MVNO carrier C provides a communication service usinga network (virtual network) constructed by borrowing at least a part ofthe owned facility 10A of the MNO carrier A (the base station 11A, etc.)from the MNO carrier A.

In the United States, the terminal 1 of the user contracting with theMVNO carrier C connects to a base station 11 B of the facility 10 B of acarrier B (MNO) in the United States, and communicatively connects, froma gateway (GW) 12 B via the Internet 21 to an virtual EPC network32C-22, via a gateway (GW) 31C-22 of a data center (DC-2) 30-2 owned bythe MVNO carrier C in the United States (the same as the Japanese MVNOcarrier C, or a communication operator such as a subsidiary or a parentcompany) that provides a cloud service. As a result, Example Embodiment1 can significantly reduce an international roaming fee, which is ratherexpensive. In the United States, the MVNO carrier C provides acommunication service using a network (virtual network) constructed byborrowing at least a part of the owned facility 10B of the MNO carrier B(the base station 11B, etc.) from the MNO carrier B, for example. Whenthe terminal 1 of a user contracting with the MVNO carrier C moves fromJapan to the United States and communicates with a terminal in Japan,the terminal 1 can communicate with a terminal in Japan from the carrierA's base station 11A, via the virtual EPC network 32C-22 of the US datacenter (DC-2) 30-2 of the MVNO carrier C, the virtual EPC network 32C-1,and the gateway (GW) 31C-1 of the carrier C's Japanese data center (DC-1) 30-1. A terminal of a user contracting with the MVNO carrier caneliminate an international roaming between a carrier of the Unitedstates and a carrier of Japan, at the time of international roaming. Itis noted that in FIG. 6, “the United States (US)” is only an example andthe United States (US)” may well be replaced by another country. In FIG.6, the Internet 20 and 21 are illustrated as separate elements in Japanand the United States for the ease of description, it is a matter ofcourse, that one Internet as a whole may be used.

However, because Japan and the United States are across the counties,the terminal 1 will access data center (DC-1) 30-1 in Japan and datacenter (DC-2) 30-2 in the United States. A data center may be sharedacross the countries by Japan and the United States.

FIG. 13 is a diagram illustrating a communication apparatus 100according to the first embodiment. In Example Embodiment 1 illustratedin FIG. 6, the communication apparatus 100 may be implemented asgateways (GW) 31C-1 and 31C-22, for example. The gateways (GW) 31C-1 and31C-22 in FIG. 6 may each include the communication apparatus 100 inFIG. 13, for example. Alternatively, the gateways (GW) 31C-1 and 31C-22in FIG. 6 may be constituted by the communication apparatus 100 in FIG.13, respectively. The following describes a case where the communicationapparatus 100 is the gateway (GW) 31C-1 in FIG. 6. Referring to FIG. 13,a processing unit 102 receives a packet transferred to the gateway(31C-1), and transmits the received packet to a forwarding destinationunder control of a control unit 101. The processing unit 102 isconnected to a virtual EPC network (for example, vEPC-1 in FIG. 6) thatis included in a data center (for example, DC-1 in FIG. 6) and thatprovides a communication service by cooperating with at least a part ofcommunication facility (for example, 10A in FIG. 6) owned by a firstcarrier (carrier A) and can communicate with a second data center (forexample, DC-2 in FIG. 6) including a virtual EPC network (for example,vEPC-2 in FIG. 6) that provides a communication service by cooperatingwith at least a part of communication facility (for example, 10 B inFIG. 6) owned by a second carrier (carrier B).

The control unit 101 controls the processing unit 102 to transmit data,from the virtual EPC network (vEPC-1 in FIG. 6) of the data center (forexample, DC-1 in FIG. 6) in which the control unit 101 is installed, toa destination data center. For example, the control unit 101 controlsthe processing unit 102 such that communication data that is to betransmitted from a terminal connecting via the communication facility(10A in FIG. 6) to a virtual EPC network (32C-1 in FIG. 6) of the datacenter (DC-1 in FIG. 6) to a terminal connecting via the communicationfacility (10B in FIG. 6) to a virtual EPC network (vEPC-2 in FIG. 6) ofthe data center (DC-2 in FIG. 6), is transmitted to the data center(DC-2 in FIG. 6). The gateway (GW) 31C-22 has the same configuration(but a connection destination of the gateway (GW) 31C-22 is the firstdata center (DC-1 in FIG. 6)). At least a part of the processing of thecontrol unit 101 and the processing unit 102 may be executed by acomputer constituting the gateways (GW) 31C-1 and 31C-22.

It is noted that the communication apparatus 100 in FIG. 13 can beapplied not only the gateways (GW) 31C-1 and 31C-22 of ExampleEmbodiment 1 illustrated in FIG. 6, but also can be applied to thegateway (GW) 31C-1 , 31C-22 of other Example Embodiments belowdescribed, as well.

As described above, according to Example Embodiment 1, a roamingoperation between the same carriers (the same MVNO carrier) is performedbetween data centers of different countries.

FIG. 7 is a diagram schematically illustrating a configuration exampleof a relay apparatus that connects data centers (DC-1, DC-2) of MVNOcarrier C in Japan and the United States. Virtual EPC networks 32C-1 and32C-2 of the data centers (DC-1, DC-2) of the MVNO carriers C 30-1 and30-2 in Japan and the United States are connected to the transmissionapparatuses 40-1 and 40-2. Each of the transmission apparatuses 40-1 and40-2 includes an optic-electric conversion apparatus and anelectric-optic conversion apparatus and is connected to each other via aoptical cable network (Transport network) 41 (also including an opticalcable which is laid as a submarine cable between Japan and the UnitedStates). Communication data sent from each data center is converted intoa frame for optical transmission and transmitted between thetransmission apparatuses 40-1 and 40-2. Here, a communication networkcomposed by various routers or the like may be provided between each ofthe data centers and transmission apparatuses 40-1 and 40-2. In thiscase, a packet which is a target of an international roaming may beassociated with the transmission apparatus to which an optical cablenetwork is connected, and the gateway 31 of each data center maytransmit the packet which is a target of the international roaming tothe transmission apparatuses 40-1 and 40-2.

FIG. 8 is a diagram illustrating the first embodiment shown in FIG. 6.It is assumed that a user subscribing to a MVNO carrier C moves fromJapan to the United States to perform an international roaming. InJapan, the terminal 1 contracting with the MVNO carrier C uses afacility of a MNO carrier A (such as a base station 11 A) to connect viathe Internet 20-1 to a virtual EPC network 32C-1 in the data center ofthe MVNO carrier C (DC-1) 30-1 (1).

The user moves to the United States (2). The terminal 1 of the user usesa facility of the MNO carrier B (such as base station 11 B) to connectvia the Internet 20-2 to a virtual EPC network 32C-2 in the data centerof the MVNO carrier C (DC-2) 30-2 and initiates communication by roaming(3).

In this way, the terminal access in the United States is made to thedata center (DC-2) 30-2 of the MVNO carrier C, as same as in Japan,thereby eliminating an inter-carrier roaming.

It is to be noted that the configuration of FIG. 6 can be applied to acase wherein the terminal 1 in Japan communicating with a facility ownedby the carrier A uses an international roaming function to communicatewith a connection destination US terminal (the terminal communicatingwith a facility owned by the carrier B of the United States. In FIGS. 6and 8, an EPC network based on an actual machine not usingvirtualization (MVNO carrier C's own EPC) may, as a matter of course, beprovided, instead of the virtual EPC network (vEPC) in at least one ofthe data centers 30-1 and 30-2. In Example Embodiment 1, the case wherethe MVNO carrier C which is a cloud operator, borrows the facilities 10Aand 10B (the base stations 11A and 11B, etc.) owned by the carriers Aand B, in Japan and the United States, is described, but, as illustratedin FIG. 2, Example Embodiment 1 is also applicable to a terminal 1C orthe like connecting via the Internet, etc., to the data center of theMVNO carrier C, via the facility 10C (base station 11 C, etc.) owned bythe MVNO carrier C which is a cloud operator. A terminal (1C in FIG. 2)contracting with the MVNO carrier C, may connect, via the communicationfacility (10 C in FIG. 2) that the MVNO carrier has borrowed from thecarrier A and the Internet, to a first network (32C-1) of the MVNOcarrier C in the data center (DC-1) 30-1, and may connect, from thefirst network (32C-1), via a second network (32C-2) of the MVNO carrierC in the date center (DC-2) 30-2, to a second terminal which connects tothe second network (32C-2) via a communication facility that the MVNOcarrier C has borrowed from the carrier B, and the Internet.

Example Embodiment 2

FIG. 9 is a diagram illustrating Example Embodiment 2. In ExampleEmbodiment 2, a basic configuration is the same as that of ExampleEmbodiment 1 of FIG. 6, but the data center (DC-1) 30-1 and the datacenter (DC-2) 30-2 of the MVNO carrier C in Japan and in the UnitedStates are provided with a database 34C-1 and a database 34C-22,respectively. The database 34C-1 in the data center (DC-1) 30-1 storesuser information, and terminal information in the virtual EPC network32C-1 and the virtual EPC network 32C-2. The database 34C- 22 in thedata center (DC-2) 30-2 stores user information and terminal informationin the virtual EPC network 32C-2, and the virtual EPC network 32C-1. Theinformation of the databases 34C-1 and 34C-2 is synchronously managed soas to be the same. For example, in synchronization with (orasynchronously) updating of one database, replication is performed tothe other database to reflect updated contents therein.

The databases 34C-1 and 34C-2 each function as HSS (Home SubscriberServer) in the virtual EPC (vEPC-1) and the virtual EPC (vEPC-2), andstore a identifier of SIM (Subscriber Identity Module) card of aterminal 1 (IMSI (International Mobile Subscriber Identity) which istransmitted from a terminal to MME in an attach processing (attachmentrequest) of the terminal), a terminal type (international roamingsupport terminal), a unique ID given to a subscriber of the MVNO carrierC, contract information such as a type of an international roamingservice, and information for managing charge. In this embodiment, theMVNO carrier C provides communication services in Japan by borrowingfrom the MNO carrier A at least a part (for example, base station 11A,etc.) of facilities 10A owned by the MNO carrier A. In addition, in theUnited States, the MVNO carrier C, provides communication services byborrowing from the MNO carrier B at least a part (for example, basestation 11B, etc.) of facilities 10B owned by the MNO carrier B.

A terminal 1, which is a subscriber of the MVNO carrier C, initiates aconnection in the United States (transmits an attachment requestmessage) (1). A predetermined node (for example, virtual MME) of thevirtual EPC network 32C-2 (vEPC-2) in the data center (DC-2) 30-2 of theMVNO carrier C in the United States, based on the identificationinformation (IMSI), confirms the user information registered in thedatabase 34C-2 functioning as HSS (2). A predetermined node (forexample, a virtual MME) of the virtual EPC network 32C-2 (vEPC-2) in thedata center (DC-2) 30-2 allows the terminal 1 to connect to the virtualEPC network 32C-2 (vEPC-2), if a terminal 1 of a user registered in thedatabase 34C-2 is an international roaming support model and if the userhas an international roaming service contract. If the user of theterminal 1 is not registered in the database 34C-2, if has not made aninternational roaming service contract, or if the terminal 1 is not aninternational roaming support model, the terminal 1 is not allowed toconnect to the virtual EPC network 32C-2 (vEPC-2).

Example Embodiment 3

FIG. 10 is a diagram illustrating Example Embodiment 3.Exampleembodiment 3 is different from the configuration of Example Embodiment 2illustrated in FIG. 9 in that the database 34C-2 in the data center(DC-2) 30-2 of the MVNO carrier C in the United States is deleted. Thefollowing describes the roaming procedure.

A terminal 1 to be roamed initiates connection in the United States (1).

In response to the connection request from the terminal 1, the virtualMME 32C-3 of the virtual EPC network 32C-2 in the data center (DC-2) ofthe MVNO carrier C in the United States, issues, to the data center(DC-1) of the MVNO carrier C in Japan, a request for confirmation andinformation sharing, as to whether or not a user of the terminal 1 isregistered.

When the terminal 1 of the user registered in the database 34C-1 is aninternational roaming-compatible model and the user has an internationalroaming service contract, the virtual MME 32C-3 allows the terminal 1 toconnect to the virtual EPC network 32C-2 (vEPC-2). If the user of theterminal 1 is not registered in the database 34C-1, or has not made aninternational roaming service contract, or if the terminal 1 is not aninternational roaming support model, the terminal 1 is not allowed toconnect to the virtual EPC network 32C-2 (vEPC-2). When it is confirmedthat the user is registered in the data center (DC-1), the data center(DC-2) permits connection of the terminal 1 to the virtual EPC network32C-2 (vEPC-2).

Example Embodiment 4

FIG. 11 is a diagram illustrating Example Embodiment 4. In order toperform synchronization and information exchange between the data center(DC-1) 30-1 of the MVNO carrier C in Japan and the data center (DC-1)30-2 of the MVNO carrier C in the United States, a tunnel is establishedby gateways (GW) 31C-1 and 31C-2 of respective virtual EPC networks32C-1 and 32C-2, and communication is performed through the tunnel. Thesequences of the initiation of connection (1), information confirmationof the database 34C-2 (2), allowance f connection and start ofcommunication (3), are the same as those in FIG. 9 and the descriptionthereof will be omitted.

With respect to the gateways (GW) 31C-1 and 31C-2, a gateway (GW) on atransmitting side encapsulates a packet with a tunnel protocol and setsa destination address field of a header to a receiving side gateway(GW). A gateway (GW) on a receiving side decapsulates the packet byremoving the added header information and transfers the packet to thevirtual EPC network.

As described above, in Example Embodiments 2-4, similarly to ExampleEmbodiment 1, an access to a terminal in the United States is made tothe data center (DC-2) 30-2 of the MVNO carrier C which is the same asthat in Japan, thereby eliminating inter-carrier roaming.

Example Embodiment 5

FIG. 12 is a diagram illustrating Example Embodiment 5. FIG. 12 is thesame as the basic configuration of FIG. 6, but the first and second datacenters are not arranged in Japan and the United States, but arearranged in Japan (for example, Tokyo and Osaka). In the present ExampleEmbodiment, in Tokyo, the MVNO carrier C provides a communicationservice by borrowing from the MNO carrier A, for example, at least apart of the owned facility 10A of the MNO carrier A (base station 11A,etc.), while in Osaka, the MVNO carrier C provides a communicationservice by borrowing from the MNO carrier B, at least a part of theowned facility 10B of the MNO carrier B (base station 11B, etc.). Theinstallation location of the data center is, as a matter of course, notlimited to Tokyo and Osaka.

In Example Embodiment 5, as with each of the above-describedembodiments, an access of a terminal in Osaka is made to the data center(DC-2) 30-2 of the MVNO carrier C which is the same as that in Tokyo,thereby eliminating inter-carrier roaming.

As described above, communication is not limited to internationalroaming or the like, as long as the communication is between virtual EPCnetworks provided in data centers that are disposed apart from eachother. In Example Embodiment 5, it goes without saying that thecommunication network between the data centers 30-1 and 30-2 may includean optical cable network (for example, an optical cable network 41 inFIG. 7). In FIGS. 9 to 12, in at least on one of the data centers 30-1and 30-2, instead of the virtual EPC network (vEPC), an EPC networkbased on an actual machine without virtualization (MVNO carrier C's ownEPC) may, as a matter of course, be provided.

Each disclosure of the above-listed Patent Literatures 1-3 and NonPatent Literature 1 is incorporated herein by reference. Modificationand adjustment of each exemplary embodiment or each example are possiblewithin the scope of the overall disclosure (including the claims) of thepresent invention and based on the basic technical concept of thepresent invention. Various combinations and selections of variousdisclosed elements (including each element in each claim, each elementin each example, each element in each drawing, and so on) are possiblewithin the scope of the claims of the present invention. That is, thepresent invention naturally includes various variations andmodifications that could be made by those skilled in the art accordingto the overall disclosure including the claims and the technicalconcept.

Although not particularly limited thereto, the above-describedembodiments are listed for example, as follows.

Supplementary Note 1

-   A communication system comprising: at least a first data center    providing a cloud service to a user, the first data center    comprising:

at least a first data center providing a cloud service to a user,wherein the first data center comprises:

a first virtual network that provides a communication service incooperation with at least a part of a communication facility of at leasta first communication operator; and

a first communication unit that is operable to communicate with a secondcommunication unit in a second data center, wherein first communicationunit is operable to transmit to the second communication unit,communication data to be transmitted from a first terminal connecting tothe first virtual network via the communication facility of the firstcommunication operator to a second terminal connecting via acommunication facility of a second communication operator to a secondvirtual network in the second data center, the second virtual networkproviding a communication service in cooperation with at least a part ofthe communication facility of the second communication operator.

Supplementary Note 2

-   The communication system according to supplementary note 1, wherein    the first virtual network and the second virtual network are    provided by the same virtual communication carrier.

Supplementary Note 3

-   The communication system according to supplementary note 1 or 2,    wherein the first data center and the second data center are    provided by the same virtual communication carrier.

Supplementary Note 4

-   The communication system according to supplementary note 2 or 3,    wherein a terminal contracting with the virtual communication    operator and connecting at a first location to the first virtual    network in the first data center,

connects, at a second location different from the first location, to thesecond virtual network in the second data center.

Supplementary Note 5

-   The communication system according to supplementary note 4, wherein    the first data center comprises:

a storage unit that shares, at least one of user information andterminal information of a terminal using the first virtual network andthe second virtual network stored therein, with the second data center.

Supplementary Note 6

-   The communication system according to supplementary note 5, wherein    in the first data center, the first communication unit in response    to a connection request from the terminal to the second virtual    network in the second data center, receives an inquiry issued from    the second virtual network, the first communication unit checks    whether the terminal is registered in the storage unit, and the    first communication unit, and

if the terminal is registered, the first communication unit allows theterminal to connect to the second virtual network, and startcommunication by roaming of the terminal.

Supplementary Note 7

-   The communication system according to any one of supplementary notes    1 to 6, wherein the first virtual network in the first data center    includes a virtualized core network.

Supplementary Note 8

-   A communication apparatus constituting a network of a first data    center that provides a cloud service to a user, the apparatus    comprising

a first unit configured to connect to a first virtual network that isincluded in the first data center and provides a communication servicein cooperation with at least a part of a communication facility of afirst communication operator, the first unit being operable tocommunicate with a second data center including a second virtual networkproviding a communication service in cooperation with at least a part ofthe communication facility of a second communication operator; and

a second unit configured to control a transmission destination ofcommunication data transmitted by the first unit, the second unitcontrolling the first unit to transmit to the second data center,communication data that is to be transmitted from a first terminalconnecting via a communication facility of the first communicationoperator to the first virtual network to a second terminal connectingvia a communication facility of a second communication operator to thesecond virtual network.

Supplementary Note 9

-   The communication apparatus according to supplementary note 8,    wherein the first virtual network and the second virtual network are    provided by the same virtual communication carrier.

Supplementary Note 10

-   The communication apparatus according to supplementary note 8 or 9,    wherein the first data center and the second data center are    provided by the same virtual communication carrier.

Supplementary Note 11

-   The communication apparatus according to any one of supplementary    notes 8 to 10, wherein at least one of the first virtual network and    the second virtual network includes a virtualized core network.

Supplementary Note 12

-   A communication method comprising:

a first data center that provides a cloud service, by using a firstvirtual network that provides a communication service in cooperationwith at least a part of a communication facility of a firstcommunication operator, and a first communication unit, being operableto communicate with a second communication unit in a second data centerthat provides a cloud service and a second virtual network that providesa communication service in cooperation with at least a part ofcommunication facility of a second communication operator; and

communication data from a first terminal connecting via thecommunication facility of the first communication operator to the firstvirtual network in the first data center, being capable to betransmitted via the first communication unit of the first data centerand via the second communication unit of the second data center, to asecond terminal connecting via the communication facility of the secondcommunication operator to the second virtual network in the second datacenter.

Supplementary Note 13

-   The communication method according to supplementary note 12, wherein    the first virtual network and the second virtual network are    provided by the same virtual communication carrier.

Supplementary Note 14

-   The communication method according to supplementary note 12 or 13,    wherein the first data center and the second data center are    provided by the same virtual communication carrier.

Supplementary Note 15

-   The communication method according to supplementary note 13 or 14,    comprising:

a terminal of a user contracting with the virtual communicationoperator, at a first location, connecting to the first virtual networkin the first data center,

at a second location different from the first location, accessing to asecond data center provided apart from the first data center andincluding a second virtual network of the virtual communicationoperator, and connecting to the second virtual network.

Supplementary Note 16

-   The communication method according to supplementary note 15,    comprising

the first data center sharing with the second data center, at least oneof user information and terminal information of a terminal using thefirst virtual network and the second virtual network.

Supplementary Note 17

-   The communication method according to supplementary note 16,    comprising:

the first data center, in response to a connection request from theterminal to the second virtual network in the second data center,receiving an inquiry issued from the second virtual network;

checking whether the terminal is registered in the storage unit; and

if the terminal is registered, allowing the terminal to connect to thesecond virtual network, to start communication by roaming of theterminal.

Supplementary Note 18

-   The communication method according to any one of supplementary notes    12 to 17, wherein the first virtual network in the first data center    includes a virtualized core network.

Supplementary Note 19

-   A non-transitory computer-readable recording medium storing therein    a program causing a computer of a communication apparatus    constituting a network in a first data center providing a cloud    service to a user, to execute:

a first processing to connect to a first virtual network that isincluded in the first data center and provides a communication servicein cooperation with at least a part of a communication facility of afirst communication operator, the first processing operable tocommunicate with a second data center including a second virtual networkproviding a communication service in cooperation with at least a part ofthe communication facility of the second communication operator; and

a second processing to control a transmission destination ofcommunication data transmitted by the first processing,

the second processing controlling the first processing to transmit tothe second data center, communication data that is to be transmittedfrom a first terminal connecting to the first virtual network via acommunication facility of the first communication operator to a secondterminal connecting via a communication facility of a secondcommunication operator to the second virtual network.

Supplementary Note 20

-   The non-transitory computer-readable recording medium according to    supplementary note 19, wherein the first virtual network and the    second virtual network are provided by the same virtual    communication operator.

Supplementary Note 21

-   The non-transitory computer-readable recording medium according to    supplementary note 19 or 20, wherein the first data center and the    second data center are provided by the same virtual communication    operator.

Supplementary Note 22

-   The non-transitory computer-readable recording medium according to    any one of supplementary notes 19 to 21, wherein at least one of the    first virtual network and the second virtual network includes a    virtualized core network.

1. A communication system comprising: at least a first data centerproviding a cloud service to a user, wherein the first data centercomprises: a first virtual network that provides a communication servicein cooperation with at least a part of a communication facility of atleast a first communication operator; and a first communication unitthat is operable to communicate with a second communication unit in asecond data center, wherein first communication unit is operable totransmit to the second communication unit, communication data to betransmitted from a first terminal connecting to the first virtualnetwork via the communication facility of the first communicationoperator to a second terminal connecting via a communication facility ofa second communication operator to a second virtual network in thesecond data center, the second virtual network providing a communicationservice in cooperation with at least a part of the communicationfacility of the second communication operator.
 2. The communicationsystem according to claim 1, wherein the first virtual network and thesecond virtual network are provided by the same virtual communicationoperator.
 3. The communication system according to claim 1, wherein thefirst data center and the second data center are provided by the samevirtual communication operator.
 4. The communication system according toclaim 2, wherein a terminal contracting with the virtual communicationoperator and connecting at a first location to the first virtual networkin the first data center, connects, at a second location different fromthe first location, to the second virtual network in the second datacenter.
 5. The communication system according to claim 4, wherein thefirst data center comprises: a storage unit that shares, at least one ofuser information and terminal information of the terminal that uses thefirst virtual network and the second virtual network stored therein,with the second data center.
 6. The communication system according toclaim 5, wherein in the first data center, the first communication unitin response to a connection request from the terminal to connect to thesecond virtual network in the second data center, receives an inquiryissued from the second virtual network, the first communication unitchecks whether the terminal is registered in the storage unit, and ifthe terminal is registered in the storage unit, the first communicationunit allows the terminal to connect to the second virtual network andstart communication by roaming of the terminal.
 7. The communicationsystem according to claim 1, wherein the first virtual network in thefirst data center includes a virtualized core network.
 8. Acommunication apparatus constituting a network of a first data centerthat provides a cloud service to a user, the apparatus comprising afirst unit configured to connect to a first virtual network that isincluded in the first data center and provides a communication servicein cooperation with at least a part of a communication facility of afirst communication operator, the first unit being operable tocommunicate with a second data center including a second virtual networkproviding a communication service in cooperation with at least a part ofthe communication facility of a second communication operator; and asecond unit configured to control a transmission destination ofcommunication data transmitted by the first unit, the second unitcontrolling the first unit to transmit to the second data center,communication data that is to be transmitted from a first terminalconnecting via a communication facility of the first communicationoperator to the first virtual network to a second terminal connectingvia a communication facility of a second communication operator to thesecond virtual network.
 9. The communication apparatus according toclaim 8, wherein the first virtual network and the second virtualnetwork are provided by the same virtual communication operator.
 10. Thecommunication apparatus according to claim 8, wherein the first datacenter and the second data center are provided by the same virtualcommunication operator.
 11. The communication apparatus according toclaim 8, wherein at least one of the first virtual network or the secondvirtual network includes a virtualized core network.
 12. A communicationmethod comprising: a first data center that provides a cloud service, byusing a first virtual network that provides a communication service incooperation with at least a part of a communication facility of a firstcommunication operator, and a first communication unit, being operableto communicate with a second communication unit in a second data centerthat provides a cloud service and a second virtual network that providesa communication service in cooperation with at least a part ofcommunication facility of a second communication operator; andcommunication data from a first terminal connecting via thecommunication facility of the first communication operator to the firstvirtual network in the first data center, being capable to betransmitted via the first communication unit of the first data centerand via the second communication unit of the second data center, to asecond terminal connecting via the communication facility of the secondcommunication operator to the second virtual network in the second datacenter.
 13. The communication method according to claim 12, wherein thefirst virtual network and the second virtual network are provided by thesame virtual communication operator.
 14. The communication methodaccording to claim 12, wherein the first data center and the second datacenter are provided by the same virtual communication operator.
 15. Thecommunication method according to claim 13, comprising: a terminal of auser contracting with the virtual communication operator, at a firstlocation, connecting to the first virtual network in the first datacenter; and the terminal, at a second location different from the firstlocation, accessing to a second data center provided apart from thefirst data center and including a second virtual network of the virtualcommunication operator, and connecting to the second virtual network.16. The communication method according to claim 15, comprising the firstdata center sharing with the second data center, at least one of userinformation and terminal information of the terminal using the firstvirtual network and the second virtual network.
 17. The communicationmethod according to claim 16, comprising: the first data center, inresponse to a connection request from the terminal to connect to thesecond virtual network in the second data center, receiving an inquiryissued from the second virtual network; checking whether the terminal isregistered in a storage unit of the first data center; and if theterminal is registered in the storage unit, allowing the terminal toconnect to the second virtual network, to start communication by roamingof the terminal.
 18. The communication method according to claim 12,wherein the first virtual network in the first data center includes avirtualized core network. 19-23. (canceled)
 24. The communication systemaccording to claim 1, wherein the first terminal contracting with avirtual communication operator connects, via the communication facilitythat the virtual communication operator borrows from the firstcommunication operator or a communication facility owned by the virtualcommunication operator, to the first virtual network in the first datacenter, and from the first virtual network, via the second virtualnetwork provided by the virtual communication operator in the seconddata center, to a second terminal connecting via the communicationfacility that the virtual communication operator borrows from the secondcommunication operator or a communication facility owned by the virtualcommunication operator to the second virtual network.
 25. Thecommunication method according to claim 12, comprising: the firstterminal that contracts with a virtual communication operator,connecting via the communication facility that the virtual communicationoperator borrows from the first communication operator or acommunication facility owned by the virtual communication operator tothe first virtual network in the first data center, and from the firstvirtual network, via the second virtual network provided by the virtualcommunication operator in the second data center, to the second terminalconnecting via the communication facility that the virtual communicationoperator borrows from the second communication operator or acommunication facility owned by the virtual communication operator tothe second virtual network.